Ambrosiea.] composite. 181 



19. XANTHIUM, Linn. 



Flower-heads monoecious. Males globular, many-flowered. Involucral 

 bracts small, in a single series. Eeceptacle cylindrical, chaffy. Florets tubu- 

 lar, 5 -toothed. Females ovoid, 2-flowered. Involucral bracts short, in 2 or 

 3 rows, the 2 inner ones large, consolidated into a hard ovoid 2-celled mass, 

 very prickly outside and terminating in 2 conical points. Florets 1 in each 

 cell. Corolla 0. Style-branches filiform, protruding. Achene obovoid. 

 Pappus 0. 



A genus of two or perhaps three species, from the Mediterranean region or the Levant, but 

 spread as weeds over a great part of the world. 



1. X. strumarium, Linn.; DC. Prod. v. 523. A coarse scabrous or 

 pubescent annual, 1 to 2 ft. high. Leaves on long stalks, rather large, broadly 

 cordate, coarsely toothed, angular or broadly 3-lobed. Flower-heads in axil- 

 lary or terminal clusters or short racemes, the upper ones male, the lower 

 female, sessile, forming, when in fruit, ovoid burrs 6 to 8 lines long, covered 

 with hooked prickles, the stout short conical beaks erect or turned inwards. 

 — X indicum, Roxb. ; DC. 1. c. ; Wight, Ic. t. 1104. X inaquilaterum,~DG. 

 1. c. X discolor, X Roxbarghii, and X brevirostris, Wallr. ; Steetz in Seem. 

 Bot. Her. 390. 



In waste places, Hance, Wright. A common weed, in most temperate and warm regions 

 of the globe. 



Tribe VI. HELTANTHE^. 



Leaves opposite, or very rarely alternate. Flower-heads usually heteroga- 

 mous, the female florets ligulate, rarely irregular or wanting, the hermaphro- 

 dite or males tubular, 4- to 5 -toothed. Eeceptacle chaffy. Anthers obtuse at 

 the base. Style of the Senecionidece or approaching that of Asteroidece. Pappus 

 of stiff awns, on short scales, or rarely none. 



20. ECLIPTA, Linn. 



Flower-heads "heterogamous. Florets of the circumference female, shortly 

 ligulate, narrow, in few series. Disk-florets hermaphrodite, 4 -toothed. Invo- 

 lucre of about 2 rows of broad almost leafy bracts. Scales of the receptacle 

 narrow-linear. Style-branches in the disk-florets linear, flattened, obtuse. 

 Achenes of the ray triangular, of the disk flattened. Pappus none, or reduced 

 to a border of minute teeth. — Leaves opposite. 



Besides the subjoined species, some Brazilian perennials are included in the genus, but 

 perhaps not correctly so. 



1. E. alba, Hank.; Miq. Ft. Ned. Ind. ii. 65. A branching annual, usually 

 prostrate or creeping, sometimes ascending or erect, 1 ft. long or more, 

 sprinkled with closely appressed short stiff hairs. Leaves shortly stalked, 

 from nearly ovate to oblong-lanceolate or almost linear, 1 to 2 in. long, 

 coarsely toothed or nearly entire. Peduncles in the upper axils single or 2 

 together, very variable in length, bearing a single flower-head about 3 lines 

 diameter. Ray-florets small, white. — E. erecta and E. prostrata, Linn., and 

 the whole section Eueclipta,DC Prod. v. 490. 



Frequent in rice-fields, Wilford ; also Wright and Seemann. A common weed throughout 

 the warmer regions of the globe. 



